I think I have found the perfect insert

[Anglepoise]

A post from precisionworks around six months ago got me experimenting with inserts designed for aluminum. By selecting a grade that works with other metals, I don't need a large number of holders or inserts.


This insert grade works perfectly with Aluminium,Stainless steel and Titanium.

Its H10, polished and ground, no coating fine grain carbide.

One style chipbreaker , high positive 25° at tip, 20°on side. Positive allows little stress on the part being machined and very light clamping in chuck will hold parts well. Designed primarily for machining aluminium, but works very well on SS and Ti.

Chipbreaker syle is AL


Triangle shape with three cutting edges. Economical yet triangle shape is strong enough for most of my work that would be classified as ‘finishing’.

( Use any shape insert you like that is available from your supplier. The key is grade and chipbreaker )

 

[precisionworks]

What's the ANSI letter-number designation for that insert?

Nice shape, great for getting into tight corners.

 

[Anglepoise]

What's the ANSI letter-number designation for that insert?
.

TCGX 2(1.5)1-AL....H10

 

[Mirage_Man]

I've been using CCGT inserts for quite some time. They also have a positive rake although I don't think as high as the one you pictured.

I've been looking at getting a few new tool holders that use the slightly larger more readily available inserts. The one I have now was the right size for when I had the Heavy Ten. Now I can go up a size to inserts with a 3/8" I.C. Whatever insert I go with I want holders that are available in L and R.

What's the lead angle on that holder? The one I use has a 5 degree.

 

[Anglepoise]

What's the lead angle on that holder? The one I use has a 5 degree.

The holder show has a -1° Lead Angle.

 

[Tekno_Cowboy]

Looks like what I should have bought. :ohgeez:

Where did you pick those up at?

 

[Anglepoise]

I've been using CCGT inserts for quite some time. They also have a positive rake although I don't think as high as the one you pictured.

I've been looking at getting a few new tool holders that use the slightly larger more readily available inserts. The one I have now was the right size for when I had the Heavy Ten. Now I can go up a size to inserts with a 3/8" I.C. Whatever insert I go with I want holders that are available in L and R.

Have a close look at the pic below

If you look carefully, one would think that the insert shown was 24° at the tip and 7° down the side. That is not the case. The tip rake of 24° does not start till 0.12 mm ( or 5 thou ) back from the edge. So if you were taking a one thou clean up cut, your effective angle would be 8°.

So for me the chipbreaker becomes very important, as it defines the true positive nature of the insert.

 

[KowShak]

You're right about the rake on that insert not starting at the cutting edge, it has a "land" with 0 degree rake and its the land that does the cutting. The chipbreaker is behind the land and is just that, i.e. its a chipbreaker and doesn't do the cutting.

Where does the geometry change over from having the positive rake to the neutral rake? How does the geometry changeover compare to the maximum DOC for that insert, i.e. does the manufacturer recommend cutting on the positive rake part of the insert or not?

According to the ANSI and ISO standards negative inserts such as CNMG, DNMG, TNMG, WNMG etc also have that land and therefore a 0 degree rake at the cutting edge.

precisionworks mentioned his favourite inserts for cutting aluminium, they are described as being a CNMG, despite having positive rake, which would suggest that they should be desribed as a CNMP or CNMS insert. If they have similar geometry as the insert you've posted pictures of above, they possibly could be correctly described as CNMG or CNMP / CNMS since they have both sets of geometry at the same time... they probably could be described as CNMX too.

 

[Anglepoise]

Where does the geometry change over from having the positive rake to the neutral rake?
.

With complex chipbreaker designs, that's a good question. Your post and picture explain what I was trying to get across better than mine.

And does the land length increase as the insert gets bigger? Mirage_Man
is considering bigger inserts to match his new lathe, but will he have as many options in positive rake inserts I wonder.

The AL chipbreaker design I now use has no land and looks like the bottom
picture in your post. It gives up some strength at the edge but with light DOC I am still getting benefit from the full 25°.

For the relatively light machines we have, and the fact that our flashlight interests usually means we will be turning 'thin wall tubing', chipbreaker selection becomes even more important.

 

[wquiles]

A post from precisionworks around six months ago got me experimenting with inserts designed for aluminum. By selecting a grade that works with other metals, I don't need a large number of holders or inserts.


This insert grade works perfectly with Aluminium,Stainless steel and Titanium.

Its H10, polished and ground, no coating fine grain carbide.

One style chipbreaker , high positive 25° at tip, 20°on side. Positive allows little stress on the part being machined and very light clamping in chuck will hold parts well. Designed primarily for machining aluminium, but works very well on SS and Ti.

Chipbreaker syle is AL


Triangle shape with three cutting edges. Economical yet triangle shape is strong enough for most of my work that would be classified as ‘finishing’.

( Use any shape insert you like that is available from your supplier. The key is grade and chipbreaker )


(snip pic)

Same here. Unfortunately for my pocket book, credit card, budget, I also listen to Barry :ohgeez:

Here is my CNMG for Al, with the positive edge. And Barry was right, it works MUCH better than other stuff I used before. I even tried on steel, and yes, it works great on steel as well:

Will

 

[StrikerDown]

Will,

If your pocket book needs help I would love to buy one of those inserts from you!

As far as that goes I would love to but one even if your pocket book didn't need help. :grin2:

 

[precisionworks]

Here is my CNMG for Al, with the positive edge ... it works MUCH better than other stuff I used before

+1

I made a couple of Al heat sinks this week for another member, and am still amazed at how well those inserts work - they seem to slice, instead of tear. I still use the conventional medium finish insert for steel & stainless steel, as those cuts tend to be much more aggressive.

I would love to buy one of those inserts from you

Ray, at $5 each (in packs of ten) they aren't really expensive. And they last a long time.

 

[StrikerDown]

+1
Ray, at $5 each (in packs of ten) they aren't really expensive. And they last a long time.

Very true but I have been saving so much money on eBay lately that I am almost tapped out. I can wait for a while, still have tons of things to do with the new hardware (like learn how it works) that will take me to another paycheck!

Still have to mill the tool holder before I need inserts!

 

[wquiles]

Will,

If your pocket book needs help I would love to buy one of those inserts from you!

As far as that goes I would love to but one even if your pocket book didn't need help. :grin2:

Very true but I have been saving so much money on eBay lately that I am almost tapped out. I can wait for a while, still have tons of things to do with the new hardware (like learn how it works) that will take me to another paycheck!

Still have to mill the tool holder before I need inserts!

Ray - Assuming that you have an CNMG 4xx series holder (like the one I am using), just send me an email with your address, and I will send you one to try out just for the postage ;)


Will

 

[StrikerDown]

Will,

I am happy to pay for the insert and the postage.

I have the same holder kit as you, it just jeeds to be milled to fit the BXA QC tool holder.

email Sent.

 

[precisionworks]

it just needs to be milled to fit the BXA QC tool holder

Ray, nothing but carbide will cut that material. Either a solid carbide end mill or a face mill with carbide inserts is needed. I killed a new, Niagara, colbalt end mill on one of those:shakehead

 

[wquiles]

Will,

I am happy to pay for the insert and the postage.

I have the same holder kit as you, it just jeeds to be milled to fit the BXA QC tool holder.

email Sent.

Payment received, and your package is ready ;)

Let me know if you have a mill or not. Like Barry said, that shank is tough!
Edit: I see that you have a mill. Then take your time and do light passes ;)


Will

Ray, nothing but carbide will cut that material. Either a solid carbide end mill or a face mill with carbide inserts is needed. I killed a new, Niagara, colbalt end mill on one of those:shakehead

Barry, when milling this tough shank, I imagine that lubrication/cooling is important (I am putting together a cool mist system similar to the Kool Mist, just waiting for the Kool Mist Formula 78 to arrive from ENCO - free shipping special!), but what about the RPM's for the mill? What would be the recommended RPM for my 5x carbide insert face mill that is 1.5" in dia?

Will

 

[KC2IXE]

Ray, nothing but carbide will cut that material. Either a solid carbide end mill or a face mill with carbide inserts is needed. I killed a new, Niagara, colbalt end mill on one of those:shakehead

I milled a insert holder the other week with HSS - no big one

 

[StrikerDown]

I milled a insert holder the other week with HSS - no big one

The brand name insert holders (High Quality holders) are at least as hard as HSS or much harder. The one in question laughs at my sharpest non-diamond files. (small exageration!)

 

[gadget_lover]

....but what about the RPM's for the mill? What would be the recommended RPM for my 5x carbide insert face mill that is 1.5" in dia?

Will

I posted a chart a while back ( http://home.earthlink.net/~dbsuthe/hss_speeds.pdf ) that can be used for guidelines. It's not a single number because the SFM is almost always expressed as a range, and it can be a wide range.

Per my chart, It looks like around 100 RPM for HSS on "hard steel". Double that for carbide, so you should run at around 150 to 200 RPM.

RPM = (3.28 times SFM) divided by diameter of the endmill.
The SFM is determined by the material you will cut. The harder the material, the lower the SFM.

I just stumbled across a great chart at http://www.endmill.com/pages/training/Speed and Feed - HSS End Mills.pdf for HSS.

They have several other good resources too.

Daniel